Aerogels are a special type of solid material with nanometre-scale pores. Porosity is often in excess of 90%, in some cases as high as 99.9%, and densities can be as low as 3 kg/m3. The unusual properties of the aerogels afford their suitability for many applications in commercial and high-tech fields, such as waste management (gas absorption, radioactive waste confinement), thermal insulation (cryogenic to high temperatures), super-insulating jackets, laser experiments, sensors (ultrasonic and gas), nuclear particle detection (Cherenkov), optics and light-guides, electronic devices, capacitors, high explosive research and catalysts.
As an example, their thermal conductivity (0.014 W/m K at room temperature) is the lowest of any solids, and they also have good transparency. Furthermore, the acoustic properties of aerogels make them effective insulators against noise, and aerogels have the lowest refractive index, and dielectric constant of all solid materials.
However, aero gel is vulnerable to moisture and tensile stress, and could be spoiled rapidly, if water or water vapour comes into contact with the material.
A research group at the University of Akron has reinforced an aero gel by incorporating a fiber in the block of the aero gel, and thereby improving the elastic properties. The American company Aspen markets various products with aero gel in a polymer matrix under the name Space Loft, but these suffer from the weakness that binding of aero gel is weak, and the material thus loses its properties over time when aero gel through physical impact is released.
KR20120082857 discloses a method for fabricating a sheet containing hydrophobic polymers and a dry gel of an organosilane surface modified water glass. The process is limited to a dry gel of water glass and hydrophobic polymers.
Water glass is cross linked with an alcohol, and subsequently hydrophobically modified with an organosilane, such as trimethylchlorosilane. The produced hydrophobically modified silica gel is dissolved in an aprotic organic solvent and mixed with a hydrophobic polymer to form an electrospinning solution. The electrospinning solution is electrospun to form a fiber. The formed fiber comprises a hydrophobic polymer component and a porous component of the hydrophobically modified silica gel. The porous component of the hydrophobically modified silica gel is formed by phase separation caused by rapid evaporation of the solvent within the hydrophobically modified silica gel. Such a structure is referred to as a xerogel. This process results in a considerable shrinkage of the porous texture which the hydrophobically modified silica gel had in the wet stage.